The present invention relates to a clamping device for coupling together in leaktight manner two smooth tubes that are disposed end-to-end, the device comprising a sealing ring that is suitable for clamping around the facing ends of the two tubes, and that has first and second free ends, each of which is provided with a sealing arrangement, the sealing arrangements being designed to procure leaktight contact between said free ends when the ring is in a tightened state, the device further comprising first and second tightening lugs suitable for being moved relative to each other in order to bring the ring into the tightened state.
In general, such a device is made of metal.
A device of this type is known from Patent Application WO 00/75548. In such a known device, the sealing ring is disposed inside a sleeve on which tightening lugs are provided. The sleeve is relatively rigid and forms a shell for the ring, which is more flexible, the sealing arrangements provided at those free ends in the form of a tongue and of a notch deforming when said ends come into contact in order to procure leaktight contact.
That device is satisfactory, but it requires a large quantity of material, which is detrimental, in particular for devices of large diameter, e.g. of diameters as from about 200 millimeters (mm).
Document U.S. Pat. No. 4,165,109 also discloses a clamping device for coupling two smooth tubes together in leaktight manner, that device comprising a ring to which a tightening assembly is fastened that comprises an hourglass-shaped lug and bolts. In that device, the ring is not surrounded over its entire periphery. However, that ring is not a sealing ring having its ends provided with sealing arrangements procuring leaktight contact between the free ends of the ring in a tightened state. Said free ends never come into contact, but rather a deformable rubber sealing gasket or the like is disposed between them. In addition, that ring is more rigid than the tightening lug, since a portion of the strip that carries said lug must be flattened during the tightening so that the separate sealing gasket performs its function. Thus, that device uses a large quantity of material because a thick ring must surround almost the entire peripheries of the tubes. It also suffers from the drawback of implementing a separate gasket, made of a material of the rubber type, that can wear prematurely.